My experience with F tagged bags in HKG was they arrived on the carousel before the buzzer sounded and the (regular, non-tagged 100's of) bags came out. After I left immigration which only took maybe 10 minutes I was waiting at the arrival carousel that had what I thought were orphaned bags from a prior flight and upon a closer look after they went around a couple laps, one was mine. By the time I hit customs the regular bags still hadn't started to come out.

In BKK in April my F tagged bag was out about 300th. I mentioned this to the CX BKK station manager then, and yesterday it was #5 out of the pipe along with other F tagged bags and in a small group of maybe 15 bags total followed by no bags at all.

It was less busy but maybe they pointed out past performance to the ground staff and it got better. All I know from opening the door of the aircraft to being in the terminal took 20 minutes most of which was walking.